Do a whois query and email the owner directly. For low amount offers going through a broker is definitely the wrong approach in my opinion.

GoDaddy has a free monitoring service [1] where you add the domain(s) you are interested in and it will email you each time that domain WHOIS data is updated. This is very useful to get notified when a domain name is about to expire and then get deleted (redemptionPeriod, pendingDelete). Over a 5+ year time period, quite a few domain names I was monitoring were eventually dropped by their previous owners. These weren't highly sought after, but your local insignificant city .com, some rather unique first/last name...these type of domain names.

[1] https://www.godaddy.com/help/setting-up-domain-monitoring-57... (not affiliated with GoDaddy; not even using them as a registrar, but this tool proved useful for me)